傅里叶变换红外显微光谱(Micro-FTIR)和X射线衍射(XRD)用于测定棉花结晶度效果比较

Study Crystallinity of the Developing Cotton Fibers by Micro-Fourier Transform Infrared Spectroscopy(FTIR)and X-Ray Diffraction(XRD)

【目的】使用傅里叶变换红外显微光谱(Micro-Fourier transform infrared spectroscopy, micro-FTIR)结合X射线衍射(X-ray diffraction, XRD)方法研究2个不同品系发育中棉纤维的纤维素结晶度(Crystalline index, CI)变化,验证micro-FTIR法测定发育中棉花纤维素CI的可行性,并用此方法对成熟棉花纤维素CI进行分析。【方法】以陆地棉0-153和海岛棉S-6为研究材料。分别获取这2个品系开花后5~30 d的棉纤维样本,取样间隔为5 d。样本清洗烘干后,获取FTIR和XRD光谱。选择4种不同FTIR结晶度(FTIR-CI)计算方法,分析2个品系棉花纤维不同发育阶段的纤维素结晶度变化,并对FTIR-CI与XRD结晶度(XRD-CI)分析结果进行回归拟合相关性分析。【结果】采用FTIR-CCI(Carrillo-Colom index)法得到的CI与XRD-CI的回归拟合相关性较高,0-153和S-6的决定系数R^2均高于0.9。将基于FTIR-CCI法的CI与XRD-CI的拟合模型用于计算随机选取的18种成熟纤维的CI(IR-CI),结果显示IR-CI虽然准确度较高,XRD-CI也在IR-CI结果的误差范围内,但是其精密度不够理想。【结论】micro-FTIR可以用于棉花纤维发育过程中结晶态纤维素累积变化研究。对FTIR-CCI法计算得到的CI与XRD-CI进行拟合建立的红外显微光谱结晶度模型可用于评估发育中棉纤维的结晶度,但是对于成熟纤维的结晶度,还需要后期使用大量的样品建立优化的研究模型。

[Objective]The change of crystalline index(CI)of two different cultivated cotton fibers at the development stage was studied by micro-Fourier transform infrared spectroscopy(micro-FTIR)and X-ray diffraction(XRD).The feasibility was verified by measuring CI in developing cotton fibers with micro-FTIR method.And it was utilized to estimate the CI of mature cotton fibers.[Method]Upland cotton 0-153 and sea island cotton S-6 were selected as examined materials.The cotton fibers of 2 varieties were obtained at 5-30 d post anthesis respectively,with a sampling interval of 5 d.After obtaining the fiber,it was washed several times with distilled water and then placed in an oven at 40℃for 48 hours.After drying,the FTIR and XRD spectra of each sample were obtained.The CI is calculated according to 4 different FTIR-CI calculation methods,the crystallinity changes of different cotton varieties in the developing period were compared,and the correlation between the FTIR-CI and XRD-CI was studied.[Result]Only FTIR-CI calculated by the Carrillo-Colom index(FTIR-CCI)had a good correlation with XRD-CI method,with higher R2 than 0.9 of both varieties.The fitting model(IR-CI)between the FTIR-CCI and XRD-CI was used to calculate the CI of the twenty-three randomly selected mature fibers.The results showed that the accuracy of IR-CI was good,and the XRD-CI results were within the error range of the calculated results according to the IR-CI model,while the precision of IR-CI could not reach anticipation.[Conclusion]Micro-FTIR can be used to study the change of cellulose in cotton fiber during the developing period.The model of IR-CI established by the correlation between the FTIR-CCI and XRD-CI,can be used to evaluate the crystallinity of developing period in cotton fiber.However,for the study of the crystallinity of mature fibers,it is necessary to use a large number of samples in the later experiment to establish an optimized model.